graph theory help

hi,

i am doing a course in graph theory but i am unable to attend its lectures because it clashes with my working hours. can anyone direct me to some good, simple, well-explained resources that would help me understand the following topics :

isomorphic graphs

graphical sequences

code trees/decode tree codes

graceful labellings of trees

finding the number of spanning trees in a graph

finding a minimum weight spanning tree for a graph

evaluating determinant by the Matrix tree theorem

also if anyone can explain to me any of the above with a suitable example, it would be greatly appreciated. Thanks.